What is the evidence that aspartate transcarbamoylase (ATCase) effects catalysis primarily by proximity? In the figure, what is the role of Lys 84' in the active site- interaction that appear to make with the substrate?
What is the evidence that aspartate transcarbamoylase (ATCase) effects catalysis primarily by proximity?
In the figure, what is the role of Lys 84' in the active site- interaction that appear to make with the substrate?
Aspartate carbamyl transferase or astartate transcarbamoylase, transfers a carbamoyl group from carbamoyl phosphate to aspartate in pyrimidine biosynthesis. this ATCase is inhibited by cytidine triphosphate CTP and uridine triphosphate UTP, the end products of the pathway stimulated by purine and ATP, by allosteric regulation.
ACTase has 6 catalytic and 6 regulatory subunits. A substrate analog N phosphonacetyl L Aspartate(PALA) is used to study ACTase. PALA binds to ACTase promoted by ATP and opposed by CTP. This binding decreases sedimentation and diffusion coeffecients of the enzyme therbybchanges the shape. there exists 2 distinct conformation of enzymes R and T. Binding of PALA to only one or two subunits of c site causes entire c6r6 flip from T to R conformation. The binding site consists of pocket between two domains of c subunit.
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